Theftproof plug



June 1937.

' A. LEWIS THEFTPRQO PLUG iled Oct 6. 1936 I am Patented June '1, 1937 I a UNITED STATES PATENT OFFICE 2,082,068 'rnnr'rrnoor PLUG Arthur Lewis, Southampton, N. Y. Application October 6, 1936, Serial No.'104,259 8 Claims 40!. 220-39) The invention relates particularly to plugs or opening 92 and the head 25 is forced against the closing means for pipes which may be installed coil ll causing it to expand and allow the head easily and simply but which may be removed only to pass therethrough in which position it may by destroying a portionvof the apparatus and by not be extracted. When the head 25 passes the 5 means of a key. spring ll it brings the enlarged portion 2| of the 5 In the accompanying drawing Figure 1 is a sealing plug 22 into and squarely against the seat plan v ew of a plug installed in a pipe or coupling 20 in the plug H. When the apparatus is thus a portion being broken away. Fig. 2 is a transproperly installed there is substantially a smooth verse vertical section on the line 2-2 of-Fig. 1. flat surface made by the face of the coupling I 10 Figs. 3, and. 5 are detail views and Fig. 6 is a the end of the plug II and the surface of the head 10 side elevation oi a key for manipulating'the plug. 2i. Preferably the diameter of the head 2| is Into the usual threaded side it of the coupling substantially the diameter of the seat 20 so that one. pipe may be inserted the plug ii proper it is impossible to insert a tool sufficiently to force which consists of a cylindrical threaded device the plug apart. In this condition the plug ii is having its inner end closed and provided on its in place and itmay not be removed because the 15 outer side with a centrally disposed rectangular Square nt al opening 2. which receives he opening l2 through most of the depth of the plug. manipulating key is closed. In order to remove Towards the bottom of the opening i2 is provided the p ug a punch 29 is applied all the center 23 a circumferentially extending circular border It and the thin closing portion 21 is punctured. The 0 cooperating to form a seat for the sealing mempunch 29 then reaches the upper end of the stem her of the plug. A washer M is provided preferof 24 and breaks the fragile key 26. This allows ably square in cross-section and corresponding the plug 23 to be removed and the plug ll then substantially to the opening l2. The member l4 may be unscrewed and removed. For this purhas a centrally disposed circular hole l5 extendpose t re m y be Provided a key Wrench 39 25 ing end to end and the circular hole I5 is exsuch as illustrated in Fig. 6 which may square panded at l6 into a larger circular opening. An in cross-section corresponding to the square elastic ring 11 preferably of spring metal may p i l2 a d m y have n e nd n p nin be compressed and seatedinthe channel it. The 3| to encircle the stem 24. Surrounding the square washer M has a circular extension l8 the stem 24 the key may be provided with a collar diameter of which is somewhat less than the 32 to rest in the seat 20. .The key 30 may be used 30 cross-section of the square hole l2. With the to initially install the plug II in place. split ring ii in place in the washer M the washer Further, the seal cap or plug 22 is not held is inserted into the square hole l2 until its square stationary in its place. It rotates and can be portion comes opposite the enlarged channel l3. manipulated around in either direction Thus 35 In this position the washer may be turned so it baiiles a prospective tamperer and the method 35 that its corners enter the channel I3 as indicated of removing the seal is made less apparent. The in Figs. 1 and 2 the extension l8 extending therefact that it is to be done by punching the center below. Inthis position atriangular spline or key of the seal does not occur to a stranger to the I! may be inserted between one flat side of \the device so readily as it might if he sees a cumberwasher l5 and a corner of the opening l2 thus some exterior cap which obviously can be removed 40 looking the washer l5 against turning. At its in no way other than by breaking. This is parupper end the opening I2 is provided with an ticularly true since nothing on the seal indicates enlarged circular seat 20 for the head 2| of the. to the uninitiated the place or manner of breaksealing plug 22. The sealing plug 22 has a ciring. Further, the fact that the seal revolves and cular extension 23 adapted to receive the shank is set in the face of the plug in such a way as to 45 of a locking bolt 24 which has at its'lower end I be inaccessible renders it impossible for a thief to an enlarged head 25 preferably having upwardly -get flaring side walls. A pin 26 of relatively fragile arrangement, the revolving seal presents the immaterial locks the bolt 24 into the closing plug possibility of gaining any purchase on the re- 22. The center portion 21 of the upper portion movable portion of the plug. If it is struck or 50 of the plug 22 is preferably made very thin and tapped at the outer edge of the seal, its rotation on the surface a mark 28 of some sort is preferhelps to preven gaining an entry at the crack ably placed at about the center of the head 2| of which would be easier were the whole thing rigid. the sealing plug 22. With the bolt 24 locked into Possibly if the seal did not revolve it might be thgplug 22 the assembled device is placed in the imp b o e a m a 01 fastening 1t 5 plug of such a fragile nature that it can be disconnected by a tap of a punch and yet be strong enough to hold the seal in place in a practical manner.

It will thus be seen that when the plug is in. place and closed it can be removed only by destroying part of the apparatus. Thus it cannot be surreptitiouslv tampered with. It cannot be opened even with a key without first destroying a part of the apparatus. Thus the present invention may be referred to as a seal device rather than a lock plug. Because the portion of the device destroyed is small and because the rest of the device can be used repeatedly by merely supplying another seal cap the plug provides efliciency combined with economy.

The plug readily lends itself for use in connection with pipes of various sorts which it is desired should not be tampered with by unauthorizedpipes, water pipes, oil pipes and other systems which might otherwise be tapped and the contents surreptitiously withdrawn. It may also be used in sealing drums or other containers which for some reason must be securely and safely sealed against tampering.

The details of construction illustrated are not essential to the present invention which may be embodied in other structures.

I claim as my invention:

1. A plug. comprising a threaded member provided with a central aperture and a closed end, a washer adapted to be seated in the aperture, a key for locking the washer in the aperture, a

spring in a seat in the washer, a shaft having an enlarged head adapted to be forced through the spring and retained thereby, a hollow stem adapted to receive the shaft and be locked thereto by a fragile key, a cover on the stem, and a seat in the plug to receive the cover and close the aperture.

2. A plug comprising a threaded member provided with a closed end and a rectilinear central aperture having an enlarged circular portion, a rectilinear washer adapted to enter the aperture and to be turned to enter the enlarged portion, a key for locking the washer in the enlarged portion, a spring in a seat in the washer, a shaft having an enlarged head adapted to be forced through the spring and retained thereby, a. hollow stem adapted to receive the shaft and be locked persons. It is especially adapted to gas thereto by a. fragile key, a cover on the stem having a weakened portion which is adapted to be broken to allow the stem to be moved to break the fragile key to release the hollow stem, and a seat in the plug to receive the cover and close the aperture.

3. A plug comprising a threaded member provided with a central aperture, a washer removably retained in the aperture, a. shaft having a head adapted to be forced into the washer and retained thereby, a hollow stem to receive the shaft and be locked thereto by a fragile key, and a cover on the stem closing the aperture.

4. A plug comprising a threaded member provided with a central aperture and a closed end, a washer seated in the aperture, a key for locking the washer in the aperture, a spring in a seat in the washer, a shaft having a. head adapted to be forced through the spring and retained thereby, a hollow stem to receive the shaft and be locked thereto by a fragile key, a cover on the stem, and a seat in the plug to receive the cover and close the aperture, said central aperture adapted to receive an opening keyadapted to rest in the seat and surround the shaft and engage the aperture.

5. In a plug a threaded member provided with an aperture, a washer held in the aperture, 9. spring in a seat in the washer, a shaft retained by the washer, a hollow stem to receive the shaft and be locked thereto by a fragile key, and a cover on the stem closing the aperture.

6. In a plug a threaded member provided with an aperture, a washer held in the aperture, a shaft retained by the washer, a. hollow stem adapted to receive the shaft, frangible connecting means between the shaft and the stem, and a cover on the stem closing the aperture.

7. In a plug a threaded member provided with an aperture, a washer held in the aperture, a shaft having a head retained by the washer, a cover closing the aperture and frangible connection means between the cover and the shaft.

8. A plug comprising a threaded member provided with an aperture, a washer held in the aperture, a spring in a seat in the washer, a shaft retained by the spring, a hollow stem adapted to receive the shaft, a cover on the stem closing the aperture, and frangible means connecting the stem and the shaft.

AR'I'HUR LEWIS. 

